"I want to make a mockup out of cheap hardware store tarp, but I need something to make my poles out of. Any idea what I can use for CHEAP testing poles?"
For scale models, I use music wire on either foam board used for signs or reinforced cork used for bulletin boards.
For full size models, you might try the fiberglass rod sold in many hardware stores to hold up driveway markers/reflectors. I've mostly used alloy poles from old tents no longer in service because the old poles have the same flex as new ones will have. But neither of these may be as 'CHEAP' as you want. PVC pipe I found too flexible to reliably simulate tent poles. For patterns, I've also tried cutting up cheap discount store tents, but without much success, as they were made from poorly sized patterns to begin with.
On Roger's AU site,
http://www.bushwalking.org.au/FAQ/DIY_RNCSummer.htm
http://www.bushwalking.org.au/FAQ/DIY_RNCSummer.htm#2M2P
-there is quite a bit of useful info about building frames from wooden panels, and a rigid wood frame will probably not only be cheaper, but produce pattern pieces that are more accurately sized. The flexing of rods makes it hard to use them for a frame that will yield pieces for a pattern that are correctly sized.
The best tents I've seen on MYOG have used the wooden frames, like Stuart's linked above. Being lazy, I've tried to use rods and tubes, and taken many years to makes tents, while others used the wooden frames and got them done in a few months. There must be a lesson in there somewhere, but it has escaped me.
My cat takes up a whole couch most of the time, much like Franco's cat takes up the whole tent mockup. Cats may be in secret psychic communication with each other everywhere about how to keep the upper hand with humans.